Pneumatic tool



Oct. 9, 1934. A. J. SGONINA PNEUMATIC TOOL Filed Aug. 12, 1951 2 Sheets-Sheet l m \mm Q 7 /1+.

1 mm s wwm mm mm N w Nm g Oct. 9, 1934. A, J. SGONINA 1,976,524

PNEUMATIC TOOL HT-ro A A/Ev? j purposes.

Patented Oct. 9, 1934 4mm STATES mem OFFICES: mmmcmqox.

Adolf J. :Sgonin'a, st. Mo. v Application 'August 12, 1931, serial no. 556,587

4 Claims. (01. 121-515) This invention relates topneumatic tools and more particula rly to that class of pneumatic tool in which a rapidsuccession of hammer blows are provided for riveting, chipping and. various other Theprimary object of this invention is to improve the balance of a pneumatic tool, thereby greatly reducing vibrations.

Another object of this invention is to provide a pneumaticrtool having two pistons synchronously operating inopposite directions.

Other and further objects and advantages 0f this invention will be'disclosed in the specification, claims and drawings, in which:-- v

l is'alongitudinal section through the tool. Fig. 2 is a cross section along the line 2 2 in Fig. 1.]

Fig. 3 is an e'levation'of the lower end of the tool. i

Fig. 4 is a plan view of the tool, partly in section andvtaken at an angle of 90 degre'esto the view i'n'Fi Jl.

Fig.15 is alongitudinal sectionof the sectional part of the view in Fig. 4. i

Fig. 6 is an elevation of the tool. I

The primary purpose of the invention, as above set forth is the production of a balanced pneumatic tool; in which two pistons 1 and 2, of equal mass, operate synchronously in opposite directions; that is to say, when piston 'l'moves up wardly, piston 2 moves downwardly, hence it is obvious that the anvil 3.will receive two blows where'heretofore with a single piston hammer it only received one blow. Therefore, the efficiency of the tool is approximately increased 100%.

For manufacturing reasons two identical cylinders 4' and 5 are provided and held in longitudinal axial alignmentby through bolts 6 and 7 which are provided with the usual heavy springs 8 for absorbing vibration. I

The adjacent ends of the cylinders land 5 are separated by the members 9 and 10 which her m'etically seal the ends of the cylinders. Between thememberse and 10 and rotatably mounted is upper end or the a ratchet wheel ll provided with pawls" in the usual manner, which are not shown nor claimed.

The anvil 3 is provided with three diameters, the largest of which, 12, is provided with a polyangular bore 13 for receiving the working tool, and also provided with a shoulder 14 for receiving the blow of the piston 2. The second diameter 15 is provided with a plurality of spirally disposed key seats 16 which engage inwardly projecting members 17 protruding from the piston 2 in order to give the anvil rotary movement. The third diameter 18 extends through the ratchetv wheel 11 and is,- also, provided with a key seat 19 which engages a projection on the ratchet wheel to prevent reversev rotation. This feature is neither shown nor .claimed'as it is usual construction. I f

.The upper end of the, cylinder 4 is hermeti cally closed. by an end-piece 20 integral with which is an operating handle 21. .Theouterend of the cylinder 5'is hermetically. closed by the member 22, which is bored and finished to pro vide a. guideway, for the, diameter 12 of the anvil3. Longitudinally disposed and rigidlyaffixed to the cylinders land ,5, by means neither shown nor claimed, is a valve chamber designated as atwhole as.23, made up of an, external housing 24 and a plurality of parts'to facilitate the manufacturing process and held together by bolts 25 and tap screws 26. A i1 The valve chamber is longitudinally-bored and finished to receive a reciprocable valve 27, which is also made of twoidenticalparts' to facilitate manufacturing. The operation of the valves and the location of the ports are identical, hence only'ytheupper: one will be described-it being understood that the lower valveis .alpduplicate thereof.. -fIT.he valve consists of a hollowicylindrical portion 28, provided with anexternal annular ring 29-. L0ngitudinally through the valve housing three bores are provided, 30 and 39 for the incoming air under high pressure, and 31 for the exhausting air. Leading to'the extremities of;;the valves through the intake port 32 are three additional bores through the valve house ing, designatedas '33. It .isobvious that a pluralityof bores are used to provide sufiicient area inthe smallest possible space, as all three of these bores 33 communicate with theinterior or hollow part of the valve, as shown at 34 in Fig. 1,;and also in Fig. 4. a t As shown inFig. 2, two external exhaust ports 35 are provided, one in intermittent communication with the cylinder 4, and the other-with the cylinder -5 These ports are screwthreaded for the purpose ofreceiving an elbow nippleso as to turn the exhausting air downwardly or away from the operator.

With the exception of the external annular rings 29 and 29a which provide a greater superficial area than the superficial area of the valve contacted by the incoming air, the valve arrangement and operation are of the conventional and usual type used in pneumatic tools.

This flow of air into the cylinders will cause 7 piston 1 to move down and strike the end-face of the anvil, 18, at the same time lifting piston 2 causing the anvil to rotate. The air displaced on the under side of pistonl and the upper side of piston 2 can flow away through ports Pa. into the longitudinal bore 39, best shown in Fig. 5,

and via the communicating channel, passes the lower end of the upper valve into the annular chamber aroundthe stems of the valves, thence through the portsil to the atmosphere.

The final 'positiono'f the pistons is shown in Fig. 1.1 The exhaust-ports 37 incylinder 4and 37min cylinder 5qare now uncovered allowing the 1 air in these cylinders to iiow' into these ports and press against the annular rings 29 and 29a of the valves, causing the valve to reciprocate.

(In the'case of cylinder 5, air flows into exhaust port 37a communicating with thewlongitudinal bore 3'1,- -which'1in turn communicates with the port. 37b).-The combined area of these two annular rings is greater than the end area contacted by the incoming air, but it is to be particularly stressed that thearea of either ring singly is lessthan said contacted end area, so that air pressure against both rings together is absolutely necessary to. actuate the valve' in either direction; as by throwingthe valve to'the right'from its previous position'shown in Fig. 1, and whereupon the lower valve portion will close off the incoming air at that side, but will 'permit of its entrythrough the-corresponding port at the upper sidelq: Thus, if either piston should travel faster-than the other to permit the incoming air to communicate with one of the annular ringsor flanges, said faster moving piston wouldfltemporarily cease its travel andwait until the other piston had moved'to the corresponding point topermit'communication with-the other flange, .andonly then would there be sufli cient pressure acting against the flanges to shift the valve.- This'synchronizes the movement of the pair of pistons, and prevents the possibility of the tool being operated with but a single one of the pistons.

-.The exhaust air from the cylinders can now flow past theannular rings 29 and 29a and out to the atmosphere through ports' 35. The incoming air can nowflow through the uppe'r hollow-reciprocablevalve through ports 38 in its closed end and via communicating channel 40 to longitudinal-bor 39, and thence to ports Pa communicating with the adjoining ends of the cylinders 4 The flow of air into thesecylinders will cause the piston l to be driven upward towards the handle and piston 2 downward to strike the anvil on its face 14. During this operation the anvil will be held against rotation by pawls engaging the ratchet wheel 11, so that piston 2 will be forced to rotate. The air displaced above piston 1 and below piston 2 will flow via ports P into the longitudinal bore 30, thence via communicating channel 42 passed the upper end of the lower valve into the annular chamber around the valve stems to the atmosphere through ports 41. When the pistons reach their final'positions, the exhaust ports 43 and 430. will be uncovered allowing-the air from the cylinders to enter and'press upon the annular rings 29 and 29a. of the valves causing them to be thrown upward. This forms a complete cycle which is repeated indefinitely during the operation of .the tool.

Having fully described my invention, what I claim as new and useful and desire to protect by Letters Patent is:-- p y 1. A pneumatic'tool of the kind described, comprising a cylinder; a pair of pistons reciprocally movable therein; air ports in saidcylinder toeither side of each of said pistons to alternately admit air thereto to actuate said pistons'inmutually opposite directions; a valve controlling" the admission of said air through said ports to said pistons; and means on said valve and operably controlled by said pistons together at a predetermined point of travel to actuate said valve.

2. A pneumatic tool of the class described, 'comprising a cylinder; a pair of pistons movable therein; a valve controlling the admission of air pressure to actuate said pistons in alternate directions; a pair or'projections spaced apart, on said valve; a port between each projection'and said cylinder and uncovered at a predetermined point oftravel'of the pistons to admit air under pressure to both of said projections in unisonlto actuate said valve. I

3. A pneumatic tool of the kind described, coma prising a cylinder having air intake. ports a pair of pistons movable therein a valve controlling the admission of air to saidpist'ons simultaneously through said ports and having end walls alternately exposed to the intakev air pressure; means on said valve to control its movement; additional ports spaced from said first-mentioned ports and communicating between saidcylinder and last-mentioned means, the effective area of said last-mentioned means and the ends of said valve being so proportioned to requireair pressure against both said means to operatefs'aid valve, to thereby synchronize the movement of the pair of pistons. v

4. A pneumatic tool of the class described, comprising a cylinder; a pair of pistons movable therein;- air ports in said cylinder at the ends of each of said pistons to alternately admit air to the latter to actuate them inmutually opposite directions; a valve controlling the admission of air through said ports; and means movable with said valve and operably controlled by said pistons together atapredetermined point of. their travel to actuate said valve.

- a ADQLF J SGrONII IA. 

